Marking of solid materials, in particular precious gemstones or the like, may be required for example in identification or quality markings. For the marking of gemstones, it is desirable that marking be performed in a manner such that the gemstone is not damaged or any damage is minimised, the integrity of the gemstone is preserved, no significant loss in mass occurs, no chemical residue remains, and the marking does not detract from the clarity or colour of the gemstone.
For ornamental gemstones, the marking technique should not be visible to the naked eye so as not to detract from the quality of the stone from an aesthetic standpoint, whereby visible identification of marking may detract from the visual result in devaluation of a gemstone.
The techniques of etching, engraving and micro-milling processes exist in the prior art, which may impact on the integrity and quality of a gemstone, and may be viewed unfavourably. Furthermore, such processes result in some amount of loss of material, again which may be viewed unfavourably.
Other marking techniques exist within the prior art including those such as disclosed in U.S. Pat. No. 6,391,215B1, whereby an information mark is applied to a polished facet of a diamond or silicon carbide gemstone whereby the gemstone is coated with an electrically conductive layer. The electrically conductive layer prevents the gemstone from becoming charged and the mark is formed by a focused ion beam whereby a portion of the surface is ablated to a requisite depth, and whereby the surface to which the mark is applied is subsequently cleaned utilising a powerful oxidizing agent.